It is commonly preferred that the fluid from a well be sample or purged. Several systems and methods have been disclosed for sampling and purge systems for well environments.
M. Lebourg, Fluid Sampling Apparatus, U.S. Pat. No. 3,104,713 (24 Sep. 1963) discloses “an apparatus for obtaining a representative fluid sample of a fluid flowing in a well when taken at a given depth and at the same time giving the amount of fluid flowing at a given time”.
M. Dean, L. Castro, and J. Salerni, Apparatus for Controlling Fluid Flow from Gas Storage Wells and Reservoirs, U.S. Pat. No. 3,580,332 (25 May 1971) disclose a “retrievable packer with a large surface area and control valve connected thereto are run and set in a cased well bore. A plug is set in the valve, after which a tubing is connected to the plug and fluid pressure applied thereto to open the valve so that gas from the well or reservoir can flow through the packer and opened valve into the tubing-casing annulus and into a gas delivery line at the top of the well bore. The valve is tapered to provide a greater annular area between it and the well casing to allow unrestricted flow of gas from the well at a very high rate. In the event of damage to the surface equipment, the well pressure automatically closes the control valve. The valve can be closed whenever desired and the tubing string removed, after which the plug and control valve and packer are removable from the well casing through use of wireline equipment, and without the necessity of “killing” the well.”
B. Nutter, Inflatable Packer Drill Stem Testing Apparatus, U.S. Pat. No. 3,876,000 (8 Apr. 1975) discloses a “drill stem testing apparatus that utilizes inflatable packer elements to isolate an interval of the borehole includes a uniquely arranged pump that is adapted to supply fluids under pressure to the elements in response to upward and downward movements of the pipe string extending to the surface. The pump includes an inner body structure connected to the packing elements and a telescopically disposed outer housing structure connected to the pipe string, said structures defining a working volume into which well fluids are drawn during downward movement, and from which fluids under pressure are exhausted and supplied to the packing elements during upward movement, the intake passages to the pump being backflushed during each upward movement to prevent clogging by debris in the well fluids.”
Drill Stem Testing Methods and Apparatus Utilizing Inflatable Packer Elements, U.S. Pat. No. 3,876,003 (8 Apr. 1975) discloses “methods and apparatus for conducting a drill stem test of an earth formation that is traversed by a borehole. More particularly, the invention concerns unique methods for performing a drill stem test through the use of spaced inflatable packer elements that function to isolate the test interval, and a pump actuated by upward and downward movement of the pipe string in a manner that enables positive surface indications of the performance of downhole equipment.”
J. Upchurch, Inflatable Packer Drill Stem Testing System, U.S. Pat. No. 4,320,800 (23 Mar. 1982) discloses a “drill stem testing apparatus that utilizes upper and lower inflatable packer elements to isolate an interval of the borehole includes a unique pump system that is adapted to supply fluids under pressure to the respective elements in response to manipulation of the pipe string extending to the surface. The pump system includes a first pump assembly that is operated in response to rotation of the pipe string for inflating the lower packer element, and a functionally separate second pump assembly that is operated in response to vertical movement of the pipe string for inflating the upper packer element. The rotationally operated pump assembly is uniquely designed to limit the inflation pressure that is supplied to the lower packer, whereas the inflation pressure generated by the vertically operated pump can be monitored at the surface.”
A. Jageler, Method and Apparatus for Obtaining Selected Samples of Formation Fluids, U.S. Pat. No. 4,635,717 (13 Jan. 1987) discloses a method and apparatus “operable on a wireline logging cable for sampling and testing bore hole fluids, transmitting the results obtained from such testing to the surface for determination whether or not the particular sample undergoing testing should be collected and brought to the surface. The apparatus comprises a downhole tool having an inflatable double packer for isolating an interval of the bore hole coupled with a hydraulic pump, the pump being utilized sequentially to inflate the double packer and isolate an interval of the bore hole and to remove fluids from the isolated interval to test chamber means where resistivity, redox potential (Eh) and acidity (pH) are determined, and finally to dispose of selected samples to one or more sample container chambers within said tool or to reject them into the bore hole if not selected.”
K. Niehaus and D. Fischer, Sampling Pump With Packer, U.S. Pat. No. 5,238,060 (24 Aug. 1993) disclose a “fluid sampling apparatus for withdrawing samples of groundwater or other fluids from a well or other monitoring site. The apparatus preferably includes pump means, packer means, conduit means and a wellhead assembly that are permanently installed at the well or monitoring site and are thereby dedicated thereto in order to avoid or minimize cross-contamination of samples from site to site. The packer is integral with the pump and isolates the groundwater below the packer in order to minimize the amount of groundwater which must be pumped in order to purge the well prior to taking an acceptable sample. The apparatus preferably also includes a removable and portable controller means adapted for easy and convenient transportation and connection to such dedicated fluid sampling components at various wells or monitoring sites.”
D. Fischer, Vented Packer for Sampling Well, U.S. Pat. No. 5,259,450 (9 Nov. 1993) discloses an apparatus “for obtaining liquid samples from a well which incorporates a vented packer. The packer reduces the amount of groundwater which must be pumped by the pump of the apparatus in order to purge the well by isolating the input of the pump to a reduced volume of groundwater. The region below the packer, which is the region in communication with the pump, is vented to the atmosphere in order to permit the pump to operate at its maximum pumping rate regardless of the recovery rate of the well. The venting of the packer eliminates the condition where the pump is trying to pull a vacuum due to a low recovery rate of the well.”
R. Schalla, R. Smith, S. Hall, and J. Smart, Well Fluid Isolation and Sample Apparatus and Method; U.S. Pat. No. 5,450,900 (19 Sep. 1995) disclose an apparatus and method for “purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. A seal may be positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Purged well fluid is stored in a riser above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion.”
R. Schalla, R. Smith, S. Hall, J. Smart, and G. Gustafson, Well Purge and Sample Apparatus and Method; U.S. Pat. No. 5,460,224 (24 Oct. 1995) disclose “The present invention specifically permits purging and/or sampling of a well but only removing, at most, about 25% of the fluid volume compared to conventional methods and, at a minimum, removing none of the fluid volume from the well. The invention is an isolation assembly with a packer, pump and exhaust, that is inserted into the well. The isolation assembly is designed so that only a volume of fluid between the outside diameter of the isolation assembly and the inside diameter of the well over a fluid column height from the bottom of the well to the top of the active portion (lower annulus) is removed. The packer is positioned above the active portion thereby sealing the well and preventing any mixing or contamination of inlet fluid with fluid above the packer. Ports in the wall of the isolation assembly permit purging and sampling of the lower annulus along the height of the active portion.”
Other documents provide technological background regarding well structures and processes, such as: PompeHydropneumatique Immrgee Pour Le Pompage Ou Le Relevement En Niveua De Liquides, FRENCH Patent Publication No. 2 758 168; C. Gloodt, Method and Apparatus for Purging Water From a Whirlpool System, U.S. Patent Application Publication No. US 2001/0027573 A1; G. Last and D Lanigan, Sampling Instruments for Low-Yield Wells, U.S. Patent Application Publication No. US 2002/0166663 A1; R. Murphy, D. Jamison, and B. Todd, Oil Well Bore Hole Filter Cake Breaker Fluid Test Apparatus and Method, U.S. Patent Application Publication No. US 2003/0029230 A1; O. Mullins, T. Terabayashi, K. Kegasawa, and I. Okuda, Methods and Apparatus for Downhole Fluids Analysis, U.S. Patent Application Publication No. US 2003/0062472 A1; J. Binder, Pneumatic Pump Switching Apparatus, U.S. Patent Application Publication No. US 2003/0138556 A1; W. Van Ee, Liquid Depth Sensing System, U.S. Patent Application Publication No. US 2003/0140697 A1; P. Williams, Oil Well Formation Tester, U.S. Pat. No. 2,511,759; G. Maly and J. Brown, Well Fluid Sampling Device, U.S. Pat. No. 2,781,663; B. Nutter, Pressure Controlled Drill Stem Tester With Reverse Valve, U.S. Pat. No. 3,823,773; F. Jandrasi and H. Purvis, Slide Valve With Integrated Removable Internals, U.S. Pat. No. 3,964,507; E. Welch, Clean in Place Diaphragm Valve, U.S. Pat. No. 4,339,111; J. McMillin, G. Tracy, W. Harvill, and W. Credle, Pneumatically Powerable Double Acting Positive Displacement Fluid Pump, U.S. Pat. No. 4,354,806; W. Martin and S. Whitt, Down Hole Steam Quality Measurement, U.S. Pat. No. 4,409,825; B. Doremus and J-P Muller, Remote Hydraulic Control Method and Apparatus Notably for Underwater Valves, U.S. Pat. No. 4,442,902; E. Chulick, Multiple Point Groundwater Sampler, U.S. Pat. No. 4,538,683; W. Blake, Jacquard Fluid Controller for a Fluid Sampler and Tester, U.S. Pat. No. 4,573,532; W. Dickinson and C. Baetz, Two Stage Pump Sampler, U.S. Pat. No. 4,701,107; S. Burge and R. Burge, Apparatus for Time-Averaged or Composite Sampling of Chemicals in Ground Water, U.S. Pat. No. 4,717,473; J. Luzier, Groundwater Sampling System, U.S. Pat. No. 4,745,801; J. Jenkins, C. Jenkins, and S. Jenkins, Water Well Treating Method, U.S. Pat. No. 4,830,111; T. Zimmerman, J. Pop, and J. Perkins, Down Hole Tool for Determination of Formation Properties, U.S. Pat. No. 4,860,581; B. Welker, Purge Valve, U.S. Pat. No. 4,882,939; T. Zimmerman, J. Pop, and J. Perkins, Down Hole Method for Determination of Formation Properties, U.S. Pat. No. 4,936,139; R. Fiedler, Valve Pump, U.S. Pat. No. 5,161,956; R. Fiedler, Valve Pump, U.S. Pat. No. 5,183,391; Y. Dave and T. Ramakrishnan, Borehole Tool, Procedures, and Interpretation for Making Permeability Measurements of Subsurface Formations, U.S. Pat. No. 5,269,180; W. Heath, R. Langner, and C. Bell, Process Environment Monitoring System, U.S. Pat. No. 5,270,945; R. Nichols, M. Widdowson, H. Mullinex, W. Orne, and B. Looney, Modular, Multi-Level Groundwater Sampler, U.S. Pat. No. 5,293,931; R. Burge and S. Burge, Ground Water Sampling Unit Having a Fluid-Operated Seal, U.S. Pat. No. 5,293,934; E. Skinner, Pitless Adapter Valve for Wells, U.S. Pat. No. 5,439,052; W. Heath, R. Langner, and C. Bell, Process Environment Monitoring System, U.S. Pat. No. 5,452,234; G. Gustafson, Service Cable and Cable Harness for Submersible Sensors and Pumps, U.S. Pat. No. 5,857,714; R. Peterson, Deep Well Sample Collection Apparatus and Method, U.S. Pat. No. 5,934,375; G. Granato and K. Smith, Automated Groundwater Monitoring System and Method, U.S. Pat. No. 6,021,664; F. Patton and J. Divis, In Situ Borehole Sample Analyzing Probe and Valved Casing Coupler Therefor, U.S. Pat. No. 6,062,073; J. Divis and F. Patton, System for Individual Inflation and Deflation of Borehole Packers, U.S. Pat. No. 6,192,982 B1; F. Patton and J. Divis, Measurement Port Coupler for Use in a Borehole Monitoring System, U.S. Pat. No. 6,302,200 B1; W. Thomas and G. Morcom, Well Production Apparatus and Method, U.S. Pat. No. 6,454,010 B1; D. Mioduszewski, D. Fischer, and D. Kaminski, Bladder-Type Sampling Pump Controller, U.S. Pat. No. 6,508,310 B1; G. Last and D. Lanigan, Method and Apparatus for Sampling Low-Yield Wells, U.S. Pat. No. 6,547,004 B2; P-E Berger, V. Krueger, M. Meister, J. Michaels, and J. Lee, U.S. Pat. No. 6,581,455 B1—Modified Formation Testing Apparatus With Borehole Grippers and Method of Formation Testing; and G. Granato et al; Automated Ground-Water Monitoring With Robowell: Case Studies and Potential Applications; Proc. SPIE Int. Soc. Opt. Eng.; vol. 4575, p. 32–41; Conf. SPIE; Nov. 1–2, 2001; Newton, Mass., USA;© 2003, IEE.
BARCAD® well systems, available through Besst, Inc., of Larkspur, Calif., comprise groundwater-sampling instruments which are designed for permanent installation at a fixed level in a uncased, backfilled borehole borehole and use gas displacement pumping. The sampler contains a one-way check valve and a porous filter, through which water can be extracted from the formation and conducted to the surface, through a narrow diameter sample return line. A BARCAD® system is placed at the bottom of a small, typically 1 inch, diameter PVC or stainless steel riser pipe, which acts as both a reservoir and as a pressure vessel during purging and sampling operations. A one-way check valve is an attached integral component of a BARCAD® system. A BARCAD® system is purged and sampled by first sealing the top of the riser pipe with a cap, which has an inlet for compressed gas and also allows the sample return line to extend out through the cap. The end of the sample return line is open to atmospheric pressure, while the connection between the outside of the sample return line and the cap is tightly sealed. Pressurized inert gas is introduced via the inlet into the riser pipe, which pushes down on the water inside the riser pipe, and closes the check valve. The gas pressure then forces the water up the sample return line to the surface. When the riser pipe has been emptied of water, the tube connecting the inert gas source to the cap inlet is opened to the atmosphere and the compressed gas inside the riser pipe then vents back down to atmospheric pressure. Formation water pressure then opens the check valve and refills the riser pipe to the formation's piezometric water level.
Prior BARCAD®-type direct pressure pneumatic sampling systems have an integral valve which cannot be removed without the removal of the entire system, which includes the riser pipe, the valve, and the primary filter or screen. When Barcad systems are buried directly in a borehole, removal is not possible, and can be difficult when a BARCAD® system is placed inside of a well.
It would be advantageous to provide a purging or sampling system sampling system includes a valve which may be removed after the system has been installed in a well or borehole, such as to allow for replacement of a damaged, stuck, or otherwise failed valve from an implanted Barcad type sampling system, without removal of the system filter or riser pipe, or to temporarily remove the valve from a Barcad type system to allow for better aquifer testing than is possible with the valve in place. The development of such a purging or sampling system would constitute a significant technological advance.
Gas displacement pumps are also used as purge pumps in conjunction with bladder type sampling pumps. The purge pump and bladder pump are hung near each other and below static water level inside of a monitoring well. Such purge pumps consist of a cylindrical chamber with a one-way check valve at the bottom, and a pair of tubes which extend from the top of the chamber to the ground surface. One tube is the gas inlet line which ends at the top of the chamber. A second line comprises a water return line, which enters the top of the chamber and ends near the bottom of the chamber. Compressed gas or air is pushed down the gas in line, which closes the valve and forces the water inside the chamber up the water return line to the ground surface. The valve in such systems is an integral part of the chamber. A limit for such purge pumps is that the diameter of the return line represents a set of trade offs. If the diameter is small, the flow rate is reduced, but there is little mixing between the water and the compressed gas powering the system. With an increased diameter, the flow rate increases, but the gas usage rapidly increases, due to gas mixing into the water in the return line once the pump chamber has been emptied. These problems become more significant with increasing pumping depth which is one reason such pumps are generally used at shallow depths, typically 250 feet or less.
While bladder type sampling pumps also operate on the gas displacement principle, bladder pumps differ from conventional purge pumps, as described above, in that the gas used to drive the system in isolated from direct contact with the fluid being pumped by an expandable bladder inside of the cylindrical chamber. The valve and the bladder are integral parts of the cylindrical chamber.
The disclosed prior art systems and methodologies thus provide sampling and purging systems for well structures, but fail, in those cases where the riser pipe is part of the pump structure, to provide sampling or purging structures which provide partial removal of a pump. For example, if a purge or sampling system where the well's riser pipe is part of the pump is required to be removed, the riser pipe and surrounding structure must also be removed, which is typically impractical, impossible, or too costly, such that the borehole or, in the case of a multiport sampling system, the sampling point is typically abandoned.
The disclosed systems are also limited in that they use a single sample return line to bring water to the surface and are thus limited in flow rates. It would be advantageous to provide multiple sample return lines to enhance flow rates from gas displacement pumps.
It would be advantageous to provide a structure and method which allows existing small diameter wells, or piezometers, to be temporarily or permanently retrofit for direct pressure pneumatic pumping for purging and sampling. The development of such a purging or sampling system would constitute a major technological advance.
It would be advantageous to provide a structure and method which allows existing wells, such as small diameter wells, or piezometers, to be temporarily or permanently retrofit for direct pressure pneumatic, i.e. gas displacement, pumping for purging and sampling. The development of such a purging or sampling system would constitute a major technological advance.
Furthermore, it would be advantageous to provide a structure and method which allows placement of BARCAD® type sampling systems, by direct push methods, which can be purged and sampled by direct pressure pneumatic methods and have post installation replaceable valves. The development of such a purging or sampling system would constitute a further technological advance.
In addition, it would be advantageous to allow placement of small diameter wells inside of existing wells to act as sampling pumps whose valve can be replaced without removing the small diameter well's screen, primary filter or riser pipe. The development of such a system would constitute a further technological advance.
As well, it would be advantageous to allow for the removal of the direct pressure pneumatic system's valve without removing the well's riser pipe, primary filter or screen. The development of such a system would constitute a further technological advance.